This invention relates to a solar energy collector. More specifically, this invention relates to a compact solar collector with improved structural stability and efficiency of operation.
Solar collectors have been theorized for decades and basically operate on a principle of concentrating solar energy to heat a working fluid or solution which can be transported, stored and utilized over an extended period of time. Notwithstanding widespread knowledge of the above basic principle, solar energy collectors known in the past have not achieved a high degree of commercial acceptance and utilization.
At least one previously known solar collector comprises a transparent tube which encloses a generally linear coaxial conduit which extends through the transparent tube and then returns in a loose spiral pattern spaced about the linear conduit. A reflector member is mounted within the transparent tube and is adjustable to direct solar rays onto the linear inlet and spiral return conduits. While this system offers a degree of theoretical appeal, fluid flow within the collector is constant because the size of the tube is constant. Accordingly, flow rates must be very low or a number of units must be tied in series to provide effective heating. In addition, mechanisms which are employed to continuously regulate reflector position are subject to mechanical failure over the course of time.
Another previously known system comprises a first linear inlet conduit and a second coaxial conduit which is corrugated to define a double series of helically extending ridges and valleys. The corrugations serve to form a return spiral flow path along the entire length of the inlet conduit. A transparent heat shield coaxially surrounds both the first and second conduits and a parabolic reflecting surface is mounted at a distance about the heat shield to focus solar energy onto the exterior surface of the second conduit. This system completely isolates the first conduit from direction application of solar energy from the sun. Additionally the dual return path provides a rapid return that does not permit maximum utilization of the heating potential of the unit. Still further, the close proximity of the transparent heat shield to the second conduit does not permit full utilization of a potential for insulation of the conduit elements. Finally the parabolic reflector element is positioned by cantilever supports at a distance that jeopardizes the mechanical integrity of the unit in high winds, etc.
The difficulties suggested in the proceeding are not intended to be exhaustive, but rather are among many which may tend to reduce the effectiveness and user satisfaction of prior solar energy collector devices. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that solar energy collectors appearing in the past will admit to worthwhile improvement.